Hi,
I am an intermediate lifter, squatting around 200lbs, deadlifting around 200lbs, dipping for reps, and shoulder pressing around 80lbs for reps.

What can skinnyguy add for a guy like me? I know how to perform the exercises. I know all about training intensely but not too often to allow muscles time to recover. I also know you have to eat an awful lot to gain muscle. But I have never gained like 30lbs in three months. I gained that in my first year followed by around 15lbs in my seconds but since then my gains have slowed down.

If I understand correctly all his program is is a three day split doing around 4 sets for 1-2 exercises for each bodypart and keeping reps to around 4-8 reps.

What other value added does he provide in his program which makes it worthwhile

It's nothing amazingly revolutionary.

Compound movements, lots of carbs, lots of protein, healthy fats, training balls to the wall, getting 9 hours sleep a day, eating 6 meals a day, whey protein.

If you're doing all of the above, you're on track.

Yeah, sounds pretty much what I have been doing in the past.

Interestingly the diets he listed on his site seemed a bit paltry. I had to eat 4000 calories a day just to gain a 1lb a week of muscle and maintain on around 3000 a day. His gaining diet seemed to be around 2400 calories

Yeah, I know what you mean.

I was on a 4000kcal bulk. Not only that, but it's the only thing that kept me energized between workouts.

Sounds like your gains have been normal. When you hit a 2-3 year in bodybuilding, everything slows... welcome to REAL bodybuilding

Gloves are off pal, it's consistancy from here on in.

You can't gain 1 pound of muscle a week. 1 pound a month is already extraordinary. Just maintain your intensity and it will pay off. Slim guys simply progress a little slower.